Perry Sandeen's 4+ year collection of R-390A reflector distillates is available at http://www.r-390a.net/Redux/index.htm or at http://www.r-390a.net/faq-refs.htm - look under 'Tutorials" Perry's are organized chronologally while Wei-i Li's "Pearls" are organized by topic, so now you can have it both ways!! Enjoy! Al, WA0HQQ ..